net/rxrpc/output.c

   1 /* RxRPC packet transmission
   2  *
   3  * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
   4  * Written by David Howells (dhowells@redhat.com)
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the License, or (at your option) any later version.
  10  */
  11
  12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  13
  14 #include <linux/net.h>
  15 #include <linux/gfp.h>
  16 #include <linux/skbuff.h>
  17 #include <linux/export.h>
  18 #include <linux/udp.h>
  19 #include <linux/ip.h>
  20 #include <net/sock.h>
  21 #include <net/af_rxrpc.h>
  22 #include "ar-internal.h"
  23
  24 struct rxrpc_pkt_buffer {
  25         struct rxrpc_wire_header whdr;
  26         union {
  27                 struct {
  28                         struct rxrpc_ackpacket ack;
  29                         u8 acks[255];
  30                         u8 pad[3];
  31                 };
  32                 __be32 abort_code;
  33         };
  34         struct rxrpc_ackinfo ackinfo;
  35 };
  36
  37 /*
  38  * Fill out an ACK packet.
  39  */
  40 static size_t rxrpc_fill_out_ack(struct rxrpc_call *call,
  41                                  struct rxrpc_pkt_buffer *pkt)
  42 {
  43         rxrpc_seq_t hard_ack, top, seq;
  44         int ix;
  45         u32 mtu, jmax;
  46         u8 *ackp = pkt->acks;
  47
  48         /* Barrier against rxrpc_input_data(). */
  49         hard_ack = READ_ONCE(call->rx_hard_ack);
  50         top = smp_load_acquire(&call->rx_top);
  51
  52         pkt->ack.bufferSpace    = htons(8);
  53         pkt->ack.maxSkew        = htons(call->ackr_skew);
  54         pkt->ack.firstPacket    = htonl(hard_ack + 1);
  55         pkt->ack.previousPacket = htonl(call->ackr_prev_seq);
  56         pkt->ack.serial         = htonl(call->ackr_serial);
  57         pkt->ack.reason         = call->ackr_reason;
  58         pkt->ack.nAcks          = top - hard_ack;
  59
  60         if (after(top, hard_ack)) {
  61                 seq = hard_ack + 1;
  62                 do {
  63                         ix = seq & RXRPC_RXTX_BUFF_MASK;
  64                         if (call->rxtx_buffer[ix])
  65                                 *ackp++ = RXRPC_ACK_TYPE_ACK;
  66                         else
  67                                 *ackp++ = RXRPC_ACK_TYPE_NACK;
  68                         seq++;
  69                 } while (before_eq(seq, top));
  70         }
  71
  72         mtu = call->conn->params.peer->if_mtu;
  73         mtu -= call->conn->params.peer->hdrsize;
  74         jmax = (call->nr_jumbo_dup > 3) ? 1 : rxrpc_rx_jumbo_max;
  75         pkt->ackinfo.rxMTU      = htonl(rxrpc_rx_mtu);
  76         pkt->ackinfo.maxMTU     = htonl(mtu);
  77         pkt->ackinfo.rwind      = htonl(rxrpc_rx_window_size);
  78         pkt->ackinfo.jumbo_max  = htonl(jmax);
  79
  80         *ackp++ = 0;
  81         *ackp++ = 0;
  82         *ackp++ = 0;
  83         return top - hard_ack + 3;
  84 }
  85
  86 /*
  87  * Send an ACK or ABORT call packet.
  88  */
  89 int rxrpc_send_call_packet(struct rxrpc_call *call, u8 type)
  90 {
  91         struct rxrpc_connection *conn = NULL;
  92         struct rxrpc_pkt_buffer *pkt;
  93         struct msghdr msg;
  94         struct kvec iov[2];
  95         rxrpc_serial_t serial;
  96         size_t len, n;
  97         int ioc, ret;
  98         u32 abort_code;
  99
 100         _enter("%u,%s", call->debug_id, rxrpc_pkts[type]);
 101
 102         spin_lock_bh(&call->lock);
 103         if (call->conn)
 104                 conn = rxrpc_get_connection_maybe(call->conn);
 105         spin_unlock_bh(&call->lock);
 106         if (!conn)
 107                 return -ECONNRESET;
 108
 109         pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
 110         if (!pkt) {
 111                 rxrpc_put_connection(conn);
 112                 return -ENOMEM;
 113         }
 114
 115         serial = atomic_inc_return(&conn->serial);
 116
 117         msg.msg_name    = &call->peer->srx.transport;
 118         msg.msg_namelen = call->peer->srx.transport_len;
 119         msg.msg_control = NULL;
 120         msg.msg_controllen = 0;
 121         msg.msg_flags   = 0;
 122
 123         pkt->whdr.epoch         = htonl(conn->proto.epoch);
 124         pkt->whdr.cid           = htonl(call->cid);
 125         pkt->whdr.callNumber    = htonl(call->call_id);
 126         pkt->whdr.seq           = 0;
 127         pkt->whdr.serial        = htonl(serial);
 128         pkt->whdr.type          = type;
 129         pkt->whdr.flags         = conn->out_clientflag;
 130         pkt->whdr.userStatus    = 0;
 131         pkt->whdr.securityIndex = call->security_ix;
 132         pkt->whdr._rsvd         = 0;
 133         pkt->whdr.serviceId     = htons(call->service_id);
 134
 135         iov[0].iov_base = pkt;
 136         iov[0].iov_len  = sizeof(pkt->whdr);
 137         len = sizeof(pkt->whdr);
 138
 139         switch (type) {
 140         case RXRPC_PACKET_TYPE_ACK:
 141                 spin_lock_bh(&call->lock);
 142                 n = rxrpc_fill_out_ack(call, pkt);
 143                 call->ackr_reason = 0;
 144
 145                 spin_unlock_bh(&call->lock);
 146
 147                 _proto("Tx ACK %%%u { m=%hu f=#%u p=#%u s=%%%u r=%s n=%u }",
 148                        serial,
 149                        ntohs(pkt->ack.maxSkew),
 150                        ntohl(pkt->ack.firstPacket),
 151                        ntohl(pkt->ack.previousPacket),
 152                        ntohl(pkt->ack.serial),
 153                        rxrpc_acks(pkt->ack.reason),
 154                        pkt->ack.nAcks);
 155
 156                 iov[0].iov_len += sizeof(pkt->ack) + n;
 157                 iov[1].iov_base = &pkt->ackinfo;
 158                 iov[1].iov_len  = sizeof(pkt->ackinfo);
 159                 len += sizeof(pkt->ack) + n + sizeof(pkt->ackinfo);
 160                 ioc = 2;
 161                 break;
 162
 163         case RXRPC_PACKET_TYPE_ABORT:
 164                 abort_code = call->abort_code;
 165                 pkt->abort_code = htonl(abort_code);
 166                 _proto("Tx ABORT %%%u { %d }", serial, abort_code);
 167                 iov[0].iov_len += sizeof(pkt->abort_code);
 168                 len += sizeof(pkt->abort_code);
 169                 ioc = 1;
 170                 break;
 171
 172         default:
 173                 BUG();
 174                 ret = -ENOANO;
 175                 goto out;
 176         }
 177
 178         ret = kernel_sendmsg(conn->params.local->socket,
 179                              &msg, iov, ioc, len);
 180
 181         if (ret < 0 && call->state < RXRPC_CALL_COMPLETE) {
 182                 switch (pkt->whdr.type) {
 183                 case RXRPC_PACKET_TYPE_ACK:
 184                         rxrpc_propose_ACK(call, pkt->ack.reason,
 185                                           ntohs(pkt->ack.maxSkew),
 186                                           ntohl(pkt->ack.serial),
 187                                           true, true);
 188                         break;
 189                 case RXRPC_PACKET_TYPE_ABORT:
 190                         break;
 191                 }
 192         }
 193
 194 out:
 195         rxrpc_put_connection(conn);
 196         kfree(pkt);
 197         return ret;
 198 }
 199
 200 /*
 201  * send a packet through the transport endpoint
 202  */
 203 int rxrpc_send_data_packet(struct rxrpc_connection *conn, struct sk_buff *skb)
 204 {
 205         struct kvec iov[1];
 206         struct msghdr msg;
 207         int ret, opt;
 208
 209         _enter(",{%d}", skb->len);
 210
 211         iov[0].iov_base = skb->head;
 212         iov[0].iov_len = skb->len;
 213
 214         msg.msg_name = &conn->params.peer->srx.transport;
 215         msg.msg_namelen = conn->params.peer->srx.transport_len;
 216         msg.msg_control = NULL;
 217         msg.msg_controllen = 0;
 218         msg.msg_flags = 0;
 219
 220         /* send the packet with the don't fragment bit set if we currently
 221          * think it's small enough */
 222         if (skb->len - sizeof(struct rxrpc_wire_header) < conn->params.peer->maxdata) {
 223                 down_read(&conn->params.local->defrag_sem);
 224                 /* send the packet by UDP
 225                  * - returns -EMSGSIZE if UDP would have to fragment the packet
 226                  *   to go out of the interface
 227                  *   - in which case, we'll have processed the ICMP error
 228                  *     message and update the peer record
 229                  */
 230                 ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 1,
 231                                      iov[0].iov_len);
 232
 233                 up_read(&conn->params.local->defrag_sem);
 234                 if (ret == -EMSGSIZE)
 235                         goto send_fragmentable;
 236
 237                 _leave(" = %d [%u]", ret, conn->params.peer->maxdata);
 238                 return ret;
 239         }
 240
 241 send_fragmentable:
 242         /* attempt to send this message with fragmentation enabled */
 243         _debug("send fragment");
 244
 245         down_write(&conn->params.local->defrag_sem);
 246
 247         switch (conn->params.local->srx.transport.family) {
 248         case AF_INET:
 249                 opt = IP_PMTUDISC_DONT;
 250                 ret = kernel_setsockopt(conn->params.local->socket,
 251                                         SOL_IP, IP_MTU_DISCOVER,
 252                                         (char *)&opt, sizeof(opt));
 253                 if (ret == 0) {
 254                         ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 1,
 255                                              iov[0].iov_len);
 256
 257                         opt = IP_PMTUDISC_DO;
 258                         kernel_setsockopt(conn->params.local->socket, SOL_IP,
 259                                           IP_MTU_DISCOVER,
 260                                           (char *)&opt, sizeof(opt));
 261                 }
 262                 break;
 263         }
 264
 265         up_write(&conn->params.local->defrag_sem);
 266         _leave(" = %d [frag %u]", ret, conn->params.peer->maxdata);
 267         return ret;
 268 }
 269
 270 /*
 271  * reject packets through the local endpoint
 272  */
 273 void rxrpc_reject_packets(struct rxrpc_local *local)
 274 {
 275         union {
 276                 struct sockaddr sa;
 277                 struct sockaddr_in sin;
 278         } sa;
 279         struct rxrpc_skb_priv *sp;
 280         struct rxrpc_wire_header whdr;
 281         struct sk_buff *skb;
 282         struct msghdr msg;
 283         struct kvec iov[2];
 284         size_t size;
 285         __be32 code;
 286
 287         _enter("%d", local->debug_id);
 288
 289         iov[0].iov_base = &whdr;
 290         iov[0].iov_len = sizeof(whdr);
 291         iov[1].iov_base = &code;
 292         iov[1].iov_len = sizeof(code);
 293         size = sizeof(whdr) + sizeof(code);
 294
 295         msg.msg_name = &sa;
 296         msg.msg_control = NULL;
 297         msg.msg_controllen = 0;
 298         msg.msg_flags = 0;
 299
 300         memset(&sa, 0, sizeof(sa));
 301         sa.sa.sa_family = local->srx.transport.family;
 302         switch (sa.sa.sa_family) {
 303         case AF_INET:
 304                 msg.msg_namelen = sizeof(sa.sin);
 305                 break;
 306         default:
 307                 msg.msg_namelen = 0;
 308                 break;
 309         }
 310
 311         memset(&whdr, 0, sizeof(whdr));
 312         whdr.type = RXRPC_PACKET_TYPE_ABORT;
 313
 314         while ((skb = skb_dequeue(&local->reject_queue))) {
 315                 rxrpc_see_skb(skb);
 316                 sp = rxrpc_skb(skb);
 317                 switch (sa.sa.sa_family) {
 318                 case AF_INET:
 319                         sa.sin.sin_port = udp_hdr(skb)->source;
 320                         sa.sin.sin_addr.s_addr = ip_hdr(skb)->saddr;
 321                         code = htonl(skb->priority);
 322
 323                         whdr.epoch      = htonl(sp->hdr.epoch);
 324                         whdr.cid        = htonl(sp->hdr.cid);
 325                         whdr.callNumber = htonl(sp->hdr.callNumber);
 326                         whdr.serviceId  = htons(sp->hdr.serviceId);
 327                         whdr.flags      = sp->hdr.flags;
 328                         whdr.flags      ^= RXRPC_CLIENT_INITIATED;
 329                         whdr.flags      &= RXRPC_CLIENT_INITIATED;
 330
 331                         kernel_sendmsg(local->socket, &msg, iov, 2, size);
 332                         break;
 333
 334                 default:
 335                         break;
 336                 }
 337
 338                 rxrpc_free_skb(skb);
 339         }
 340
 341         _leave("");
 342 }